Charge-coupled devices are in wide spread commercial use. Such devices are available in linear arrays and in two dimensional array form. The cells, or light sensing elements, of a 2-dimensional CCD array are arranged in rows or columns and operated in the fashion of a parallel set of shift registers to move along the rows electrical charges, representative of a spatial distribution of incident light intensities, to a (column) shift register for read out.
The charges are moved along the rows and columns, while the CCD is shuttered from light between exposures, by a multi-phase electrical gate structure, as is well understood in the art. The gate structure is formed on the surface of the semiconductor wafer in which the light-sensitive array of cells of the CCD are defined. The structure is defined by thin layers of polycrystalline silicon deposited, via photolithographic techniques, in a multi-layer, partially overlapping configuration which partially obstructs the passage of light to the semiconductor surface. Thus, the light-sensing characteristics of a CCD array is reduced by the conductor structure required to move the representative charges generated in the CCD by incident light.